1. Field of the Invention
This invention is directed to a light weight solid state rechargeable alkaline metal or alkaline earth metal battery where the current collector and carrier includes a web of carbon fibre material.
2. Description of the Prior Art
There has been considerable interest in rechargeable alkaline metal or alkaline earth metal batteries and the components therefor due to the many advantages that they, and particularly lithium, provides when properly handled and incorporated into batteries. Examples of prior art electrochemical cells, batteries and components are found in the article by Hooper, et al. Advanced Battery Development, Odense University Press, 1984 and in the U.S. Pat. Nos. 4,357,401, to Andre et al., Bannister, 4,471,037, Sugiuchi et al., 4,496,638, Skotheim, 4,520,086, and Hope et al., 4,576,883.
As described in the prior art, solid state alkaline battery construction usually includes the deposition of an alkaline earth metal or alkaline metal, such as lithium onto a metal foil base, which base serves as a current collector and carrier.
As is known alkaline metals and alkaline earth metals are highly reactive, and are particularly suitable for use in batteries due to their ionic and electrical properties. Such metals are usually bonded or coated onto current collecting and carrying bases of metal foil such as copper, nickel or aluminum. The alkaline metals used include lithium, sodium, potassium and cesium with lithium being particularly popular for incorporation into batteries. The alkaline earth metals would include beryllium, magnesium, calcium, strontium and barium. It has been observed that while alkaline metals, such as lithium, may appear initially to not react with copper or other metal foil bases, that over a period of time the alkaline metals often react unfavorably with the metal foil and form an alloy with the metal, resulting in decreased efficiency and a shorter than desired service life. It is important that the metal foil be free from impurities but this is difficult to accomplish and the alkaline metal may also react with even minute amounts of impurities associated with the foil. The base metal foils account for as much as 50% of the total battery weight, so that a reduction in the weight is desirable and will increase the energy density of the battery. It is desirable therefore to provide a suitable current collector which reduces the total battery weight and is inert to the problems associated with the use of alkaline metals, or alkaline earth metals while enhancing their desirable properties.